STONELESS PRUNES 77 



Here it is not necessary to repeat the details of 

 the method through which the stoneless plums of 

 various kinds, including the prune, were devel- 

 oped. It seems desirable, however, to examine 

 at some length the relations that obtain between 

 the stony seed covering and the general and 

 especial needs of the plant ; and to correlate this 

 type of seed covering with other type of protec- 

 tive seed covering that serve the same or a 

 similar function in the case of other tribes of 

 plants. 



When man takes a plant under his care, some 

 of its many parts may become of little use, be- 

 cause of the changed conditions of the artificial 

 environment. 



Thus the wild oat has a pointed, sawlike beard, 

 which, turning and twisting under influence of 

 moisture and heat, helps the seed to burrow into 

 the earth. This is obviously useful to the plant 

 in a state of nature. But it becomes a useless 

 piece of baggage when the plant has been tamed 

 and grown by man, for man will see that the seed 

 is planted in return for the crop it yields. 



The blackberry, domesticated, has no further 

 use for the thorny armor that was originally de- 

 veloped to protect it from destruction by ani- 

 mals that would browse on its leaves and stems or 

 trample it to death. 



